/*
 * Copyright (c) 2020, 2023 Oracle and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.helidon.faulttolerance;

import java.util.function.Consumer;
import java.util.function.Function;

/**
 * Fallback allows the user to execute an alternative function in case the provided supplier fails.
 *
 * @param <T> type of the values returned
 */
public interface Fallback<T> extends FtHandlerTyped<T> {
    /**
     * Create a fallback based on configuration.
     *
     * @param fallbackConfig fallback configuration
     * @param <T> type of the values returned by the failing method
     * @return a new fallback
     */
    static <T> Fallback<T> create(FallbackConfig<T> fallbackConfig) {
        return new FallbackImpl<>(fallbackConfig);
    }

    /**
     * Create a fallback and customize its configuration.
     *
     * @param configConsumer consumer of configuration
     * @param <T> type of the values returned by the failing method
     * @return a new fallback
     */
    static <T> Fallback<T> create(Consumer<FallbackConfig.Builder<T>> configConsumer) {
        FallbackConfig.Builder<T> builder = FallbackConfig.builder();
        configConsumer.accept(builder);
        return create(builder.build());
    }

    /**
     * Create a fallback from the fallback method.
     *
     * @param method method to use
     * @return a new fallback
     * @param <T> fallback method return type
     */
    static <T> Fallback<T> createFromMethod(Function<Throwable, ? extends T> method) {
        return create(builder -> builder.fallback(method));
    }
}
